Catheters have widespread clinical use in both diagnostic and therapeutic procedures. For example, catheters are used diagnostically to inject contrast media, measure internal body dimensions, retrieve biopsy samples, and visually inspect internal body sites. Catheters are used therapeutically to deliver drugs, deliver implants, drain fluids, retrieve foreign and/or undesirable materials, deliver ultrasound, deliver laser light, provide access for minimally invasive surgical instruments, and dilate narrowed body passages (e.g., vessels).
In several of these procedures, it is advantageous to be able to visualize the progress of the catheter towards the target location within a patient's body. Introducing catheters into the body often requires fluoroscopic visualization to aid the treating healthcare provider in guiding the catheter to the target site. Catheters are commonly formed of a non-radiopaque polymeric material. Therefore, radiopaque markers may be added to the catheter to enable the catheter to be visualized during x-ray and fluoroscopic procedures. For example, in intravascular catheter procedures, health care providers may guide the catheter to a target location by using fluoroscopy to track the position of radiopaque markers on the catheter.
Commonly, these radiopaque markers are circumferential metallic bands affixed to the exterior surface of the catheter. Although these marker bands allow the catheter to be visualized by fluoroscopy, they can present certain problems. In particular, metallic marker bands require fixation (e.g., by crimping, swaging, or adhesive) to the underlying catheter to avoid slippage as the catheter is moved through the body. The bands may protrude from the tubular surface of the catheter and increase the catheter profile, which creates frictional resistance to the translational movement of the catheter through body passages, and potentially damages tissues contacting the moving catheter. In some instances, where a marker band has been swaged onto the outer surface of a catheter and the inner diameter of a marker band is greater than the outer diameter of the catheter, buckling may occur, causing the marker band to crack and the catheter surface to tear. Further, the placement of band markers on the outer catheter surface presents problems with inadvertent disassociation of the markers from the catheter wall, with attendant loss of positional and measurement accuracy. In addition, such marker bands are constructed from expensive and heavy radiopaque metals such as gold, platinum, tantalum, and alloys of these dense materials. The use of these heavy materials typically results in inflexible and rigid marker bands that can impair the trackability of the catheter by increasing the stiffness of the catheter, thereby compromising the flexibility and maneuverability of the catheter.
The devices, systems, and methods disclosed herein overcome one or more of the deficiencies of the prior art.